Research On Multi-Port Output Filtering Power Amplifiers

The 5th generation(5G)mobile communication systems cost great amount of energy.In order to meet the overall needs of low-carbon,environmental protection and resource conservation nowadays,demands for designing low-cost and high-efficiency power amplifier are increasing.In addition,in the 5G era,the modulation mode is becoming more and more complex,so the system nonlinearity is more and more intolerable.Therefore,the design difficulty of power amplifier has also increased greatly.The large-scale application of multiple input multiple output(MIMO)system and active antenna consumes a huge number of power amplifiers.Aiming at the new requirements of power amplifier design in 5G era,this thesis studies the theoretical basis and design methods of two new types of power amplifiers:filtering power amplifier and multi-port power amplifier.The main works of this thesis are as follows:1.To meet the design requirements of filtering power amplifier,a fast roll off filtering impedance converter is proposed.Based on this,a fast roll off filtering power amplifier is realized,which has good filtering response in the working frequency band and fast roll off characteristics beyond the working band.The measured results of S-parameters meet the expectation coming with the simulation.And it has good performance in the working band.The saturated drain efficiency reaches 57%-61%,the saturated gain is 10.0-10.8 dB,and the output power reaches 40.0-40.6 dBm.2.A high stopband rejection broadband filtering impedance converter is proposed.Based on this,a high stopband rejection broadband filtering amplifier is realized.The compensation capacitor is used to solve the sudden reduction of rejection level at high frequency caused by odd and even mode phase velocity mismatch.It has good filtering response,wide bandwidth,and a novel rejection level higher than 60 dB outside the working band.In the working band,the saturated drain efficiency reaches 55%-62%,the saturated gain is 9.1-11.2 dB,and the output power reaches 39.9-40.8 dBm.Under digital predistortion technology,the adjacent channel power ratio(ACPR)reaches-47.8 dBc.3.For the new multi-port power amplifier,a restraining network is proposed,which can suppress the specified frequency through a special structure.Based on this structure,a dual-band dual-output power amplifier is realized,which can achieve 55.84%and 53.77%drain efficiency at 3.5 GHz and 5.0 GHz.The 40%drain efficiency bandwidths over the two working bands are over 200 MHz.The two output ports can suppress unwished signals greatly.Under digital predistortion technology,ACPR can reach-47 dBc at 3.5 GHz and-48.1 dBc at 5.0 GHz.